The efficiency of reaction or separation processes is significantly affected by the way in which the feed fluid introduced to process vessels is distributed. Fluid distribution in the process vessels influences the reaction or separation surface area available to the fluid. To utilize the-maximum reaction or separation surface area, the fluid needs to be uniformly distributed in the process vessels.
In many process vessels, a fluid stream is introduced through small pipes. The fluid stream moving through the pipes flows at a high velocity and enters the process vessels normally in the head region as a jet. This jet must expand into the process vessels with about one hundred times or more the cross-sectional area to obtain a uniformly distributed flow. If the uniformly distributed flow is not obtained, the jet may propagate along the center axis of the process vessels at a high velocity. Consequently, all of the available reaction or separation surface area is not fully utilized, thereby decreasing the yield of the desired product. Even worse, particles or packings, such as catalysts or adsorbents, in the process vessels may be damaged because a high velocity jet can blow loosely filled particles or packings into the walls of the process vessels and/or can cause local fluidization at the bottom of the process vessels.
To avoid the problems associated with the pipes, an insert basket or a deflector plate, which has a slightly larger diameter than the pipes, is utilized in the process vessels. These insert basket and deflector plate have a plurality of slots or openings, which are useful for expanding a jet stream from the pipes. Though the basket or plate minimizes the problems associated with the pipes, they are not effective in generating a uniform flow velocity across the entire cross-section of the process vessels. When, for example, the basket is deep or the deflector plate is located substantially below the pipes, a substantial portion of the entering jet may turn slightly to bypass the bottom plate of the basket or the deflector plate, thus impinging on the outer section of the process vessels. If the basket is shallow or the deflector plate is located just below the pipes, the jet may turn ninety degrees and flow along the walls of the process vessels. In both situations, the velocities generated can entrain packing materials or particles on the top of the process vessels.
Therefore, there is a genuine need to find a better way to engender a uniform velocity across the entire cross-section of the process vessels having packing materials or particles. The enhancement of fluid distribution, i.e., improved uniformity, allows for the use of all the available reaction or separation surface area in the process vessels, thereby efficiently increasing the yield of the desired product.